Litter has become a weapon of class war in Britain, where a call to “Clean for the Queen” has stirred both trash-tidying volunteers and howls of anger.

The campaign, backed by charity Keep Britain Tidy and corporate sponsors including McDonalds, is urging people to spruce up their communities before Queen Elizabeth II’s 90th birthday, which is being marked in June. (Her actual birthday is April 21 — two birthdays a year are a royal perk).

“What better way could we show our gratitude to Her Majesty than to clean up our country?” the campaign asks on its Website.

A special litter-picking weekend kicked off Friday, with events scheduled across the country. Outside Parliament — one of the tidiest, most-photographed spots in the country — schoolgirls hunted valiantly for stray candy wrappers or coffee cups.

But some Britons felt insulted by the suggestion they should tidy up to honor a hereditary monarch who receives more than 35 million pounds ($50 million) a year from British taxpayers.

“I would rather swim in sewage than Clean for the Queen,” ran the headline of a column by Michele Hanson in the left-leaning Guardian newspaper.